Near the airplane after escaping. Anyone know of a big stash? Blown an hour alreadY, gets real frustrating very quickly..
There are several masks on corpses and filters in the boxes inside the buildings right past the plane as well as a few inside the underground passage before it. Here is a video of this level, the part you are looking for is around the 6:40 mark: [YOUTUBE]K4qlLE9Fiw0[/YOUTUBE] Here is the full playlist for all the levels if you need it for reference later.
